JPH0337400B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a polyphase stepping motor, and more particularly to a drive circuit for a polyphase stepping motor capable of half-step driving.

"Prior Art" Various methods have been proposed as drive means for this type of multi-phase stepping motor. For example, US Pat. By means of
Excite the corresponding winding to one polarity, or
Or, the winding is energized to the opposite polarity, or when not energized, it can take three states such that an effective short circuit is formed for the winding, and these switching means perform the above-mentioned operation according to a predetermined sequence. A multi-phase stepping motor is disclosed that includes a control circuit that allows the magnetic field generated in each winding to step in a predetermined direction at a predetermined step angle so that any one of the states can be assumed. According to such a control means, although the circuit configuration is complicated,
It is said that the damping characteristics of the motor are maintained well.

Regarding the driving means of a similar multi-phase stepping motor, FIG. 6 shows a method that can simplify the circuit configuration although the number of switching elements is increased. In the same figure, each phase winding φ1 to φ of the multiphase stepping motor
Switching elements T1 to T10 for connecting to the positive electrode side of the DC power supply at the start and end ends of 5, respectively;
Similarly, switching elements T11 to T20 are provided to connect to the negative pole side of the power supply, and for example, when half-step drive is performed, four phase windings can be energized and five phase windings can be energized for each pulse input. A driving method has also been proposed that enables so-called 4-5 phase excitation, in which states in which phase windings can be energized are alternately repeated.

``Problems to be Solved by the Invention'' According to the above-mentioned conventional drive system, the circuit configuration is generally complicated, and in particular, when half-step drive is desired for such a multi-phase stepping motor,
A large number of switch elements, for example four times the number of motor phases, are required. Therefore, the circuit configuration of the output stage becomes complicated, and the current capacity of the power supply also increases by 4 times the rated current value of the winding.
~5 times or more is required. Furthermore, there are various practical problems in realizing half-step drive of this type of multiphase stepping motor, such as an increase in the number of connections between the motor and the drive circuit, and the resulting complexity of connection work. It was hot.

"Means for Solving the Problems" The present invention was made in view of the above problems.
One purpose is to provide a multiphase stepping motor drive circuit that reduces the number of required switching elements constituting the drive circuit as much as possible, thereby simplifying the circuit configuration and reducing wiring work. It is in.

Another object of the present invention is to provide a highly practical multiphase stepping motor drive circuit in which the current capacity of the power source of the drive circuit is approximately twice the rated current of the windings.

The structure of the present invention for achieving the above object is as follows. That is, when using the method of the present invention,
Each phase winding of a polyphase stepping motor having an odd number of phases is sequentially connected at its starting end and terminal end to form a ring, and a switching means is connected to each connection point of these several phases, and In a stepping motor drive circuit configured to connect each of the connection points to the positive or negative pole of the drive power supply by switching means, or not to connect to either of the poles, the stepper motor is configured to connect the connection points to the positive pole or the negative pole of the drive power supply during driving. It is characterized in that the total number of connection points connected to the negative electrode is controlled to alternately repeat 2 or 3 every time an input pulse is received.

"Embodiments" Hereinafter, preferred embodiments of the present invention will be described in detail based on the drawings.

1 to 5 show an embodiment of a multi-phase stepping motor drive circuit according to the present invention. In Fig. 1, φ1 to φ5 indicate five-phase windings connected to each other at connection points 1 to 5, respectively, and when a circulating current flows, these windings have an electrical angle of 72 The starting and ending ends of each phase winding are sequentially connected to form a ring so that torque vectors A, B, C, D, and E shifted by degrees can be formed. T1~T5 and T6~
T10 indicates a switching element for separately connecting these windings to the positive and negative sides of the drive power source through five connection points 1 to 5 of each phase winding.
As shown in the figure, these elements are T1, T6, T
2 and T7, T3 and T8, T4 and T9, and T5 and T10 are each connected in series, and each connection point is connected to a corresponding connection point of the phase winding.

FIGS. 2 and 3 are time charts showing the operation of the drive circuit configured as described above. In the figure, first, in the case of step 1, switching elements T1, T8, and T9 are conductive, and connection point 1 of winding φ1 and winding φ5 is connected to the positive side of the drive power source, and the winding The connection point 3 between the wire φ2 and the winding φ3 and the connection point 4 between the winding φ3 and the winding φ4 are connected to the negative pole side of the power supply, thereby forming a so-called four-phase excitation state. Next, when moving to step 2, switching elements T1 and T9 become conductive, so the connection point 1
are connected to the positive side of the power supply, and the connection points 4 are connected to the negative side of the power source, so here the so-called 5
This results in a state of phase excitation. Furthermore, in the case of step 3, switching elements T1, T2
and T9 become conductive, so that connection points 1 and 2 are connected to the positive side of the power supply, and connection point 4 is connected to the negative side of the power supply, returning to the four-phase excitation state again. Thereafter, in steps 4 to 20, the 4-5 phase excitation state is repeated in sequence. Therefore, the total number of connection points connected to the positive and negative sides of the drive power source is 3 → 2.
→ Repeat alternately like 3 → 2...

FIG. 4 is a diagram showing the state of excitation step by step, and shows the states from step 1 to step 5. In the figure, white circles (○) represent connection points connected to the positive side of the power supply, black circles (●) represent connection points connected to the negative side, and arrows indicate the direction of current in each state.

A vector diagram generated by the drive circuit having such a configuration is shown in FIG. As can be seen from the figure, the vector of the resultant torque for each step is expressed in electrical angle.
It rotates in 18° increments to achieve so-called half-step drive.

Although not shown in the drawings, it is understood that the present invention can be applied to other multi-phase stepping motors other than the five-phase stepping motor of the above embodiment.

"Effects of the Invention" As explained above, according to the present invention, high-resolution positioning is possible while each switching element for driving each phase winding of a multi-phase stepping motor is configured with two elements. - It is possible to reliably achieve half-step drive using the five-phase excitation method. In such a 4-5 phase excitation method, it is only necessary to turn one phase current on or off at all times, so switching the phases is extremely easy, and this allows the circuit configuration to be significantly simplified, such as miniaturization and cost reduction. This has a practical advantage. Further, by simplifying the circuit configuration, the number of lead wires of the motor can be minimized, thereby reducing the work required to connect the motor to the drive circuit.

Since each phase winding of the multiphase stepping motor is inserted in series and parallel to the drive power source as shown in FIG. 4, the drive power source capacity can be suppressed to approximately twice the winding rated current.

Further, according to the drive circuit according to the present invention, the torque fluctuation in the four-phase excitation and five-phase excitation states during constant current driving or constant voltage driving is approximately 5% or 14%.
It is possible to keep the value to a value that does not cause any problem in practical use, and even under load, the error for each step can be ignored, and the rotational operation is extremely smooth. The present invention is optimal as a means for reducing costs and improving practical performance of this type of motor and drive circuit.

[Brief explanation of the drawing]

FIG. 1 is a wiring diagram showing an embodiment of a drive circuit for a multi-phase stepping motor according to the present invention, FIG. 2 is a conduction time chart of switching elements for each step according to the circuit of FIG. 1, and FIG. 2 is a time chart showing the excitation state of each phase winding corresponding to FIG. 2, FIG. 4 is a diagram showing the excitation state for each step, and FIG. FIG. 6 shows a vector diagram of the resultant torque during current drive, and a drive circuit connection diagram of a five-phase stepping motor that performs half-step drive according to the conventional means. T1~T20: Switching element, φ1~φ
5: Each phase winding, 1~5: Connection point of each phase winding, A~
E: Torque vector.

Claims (1)

[Claims] 1. The windings of each phase of a polyphase stepping motor having an odd number of phases are sequentially connected at their starting and ending ends to form a ring, and switching means are connected to each of the connection points of these several phases, and , in a stepping motor drive circuit configured to connect each of the connection points to a positive pole or a negative pole of a drive power supply by the switching means, or not to connect to either of the poles; 1. A drive circuit for a multiphase stepping motor, characterized in that the total number of connection points connected to the positive and negative electrodes of the motor is controlled so as to alternately repeat 2 or 3 each time an input pulse is received.